1. Field of the Disclosure
The present application relates to the technical field of valve bodies, specifically to an electronic expansion valve and a manufacture method thereof.
2. Discussion of the Background Art
Reference is made to FIG. 1, which is a schematic view showing the structure of a typical electronic expansion valve.
The electronic expansion valve includes a valve seat assembly, a housing component 64, and a valve rod assembly 130. The valve seat assembly includes a valve seat 24 and a cover 60, a first port 18 and a second port 16 are oppositely provided at a lower end of the valve seat 24, and are used to connect a first connecting pipe 18a and a second connecting pipe 16a respectively, and the first connecting pipe 18a and the second connecting pipe 16a are in a same straight line. A main valve cavity is formed by the valve seat 24, and the main valve cavity is arranged at an acute angle with respect to the first connecting pipe 18a, that is, the valve seat 24 is of a “”-like shape.
A motor 70 of the electronic expansion valve is mounted in the valve seat assembly or the housing component 64. In FIG. 1, the housing component 64 and the cover 60 cooperate to form a complete cavity to accommodate the whole motor 70. The housing component 64 and the cover 60 are connected via threads, and the cover 60 and the valve seat 24 are also connected via threads. In FIG. 1, an end of the valve seat 24 is provided with a connecting portion, and the cover 60 is connected to the connecting portion via threads. When the motor 70 rotates, the motor 70 drives the valve rod assembly 130 to rotate via a gear system 76, to allow a valve needle of the valve rod assembly 130 to block or leave a valve port, thereby cutting off or allowing the communication between the first connecting pipe 18a and the second connecting pipe 16a. 
The above technical solution has the following technical problems.
Firstly, multiple components of the electronic expansion valve are connected via threads, for example, the cover 60 of the valve seat assembly is connected to the housing component 64 via threads, the cover 60 is connected to the valve seat 24 via threads, and parts at a top of the housing component 64, such as a top cap, are also connected via threads. During a large scale assembly process, reliable seal cannot be guaranteed, and a reject rate caused by leakage is high. Besides, due to the vibration, corrosion and oxidation during a transport process and a use process, the leakage amount at a threaded connection portion may be sharply increased as the used time increases.
Secondly, in the case that a threaded connection is employed, the strength of the connection portion needs to be ensured, which requires to increase a design thickness and a weight of the material, thus resulting in a high product cost.
In view of this, it is an urgent technical issue for those skilled in the art to improve a sealing performance of the electronic expansion valve.